1. Field of the Invention
The present invention relates to an image-reading apparatus, an image processing method, and a computer program product.
2. Description of the Related Art
Some of conventional image-reading apparatuses correct color shifts of images.
For example, JP-B-6-18424 discloses an image-reading apparatus and a technique that corrects a color shift of an image by controlling driving of a motor that feeds documents. In the image-reading apparatus, another technique is disclosed that corrects the color shift by correcting an offset of a filter of a light receiving element such as a line sensor.
The conventional image-reading apparatus such as the apparatus disclosed in JP-B-6-18424, however, has a problem in that the color shift changes in a single document when the angle and the distance between a reading sensor and the document change while the reading sensor is in operation to read the document, so that color images are not truly reproduced.